Word indeed often used in tv-series "The Sopranos". It derives from Italian 'questo cazzo', which literally means 'this dick'. With a neapolitan dialect it is pronounced ''stu cazz'', or stugats. Neapolitans use it when someone is trying to tell or sell them something worthless (it can also be an indication for fake: a stugats watch). The American use has more facets, for example it can be used as a swearword towards a person.

"You think I will be paying the dinner? Stugats!"
"He just keeps telling me stugats"